Ultrasound Analysis of Lateral Ankle Ligaments in Functional Ankle Instability

The anterior talofibular ligament and the calcaneofibular ligament were sonographically investigated in 16 patients with functional ankle instability (FAI) and 16 controls under neutral and standardized stress conditions of 15 kp with a TELOS device. Clinical investigation revealed a significantly higher rate of a positive anterior drawer and talar tilt (p <0.001, respectively), significantly increased supination (p = 0.047) of the right ankle joint and increased plantarflexion (p = 0.009) of the left ankle joint in the FAI group compared with controls. Significantly higher rates of inhomogeneity and hypo-echogenicity were sonographically observed in both ligaments in the FAI group (p < 0.05, respectively). The anterior talofibular ligament was significantly longer under stress conditions, and the calcaneofibular ligament was significantly longer under both neutral and stress conditions in the FAI group (p < 0.05, respectively). Peritendinous edema of the peroneal tendons was found in 22% of the FAI group and 6% of controls.